WASHINGTON -- A growing number of Republican U.S. congressmen are backing a children's health insurance package the president has vowed to veto.

At issue is the five-year, State Children's Health Insurance Program for children living in poverty.

Senate sources told the Washington Post the bill appears to have at least 69 bipartisan votes, which would make it veto-proof by President George Bush, who maintains a White House measure that addresses the same issue through a different bill is superior.

Monday, the Post said lobbying was in high gear in the House, where Republicans there were also leaning to support the compromise measure, which increases the size of the program by $35 billion -- $30 million more than the White House wants -- and raises the income ceiling.

The administration issued new rules this month to thwart expansion.

Reps. Heather Wilson, R-N.M., and Ray LaHood, R-Ill. published a joint letter to fellow Republicans calling for support for the bill.

Sources told the Post as many as 25 Republicans would likely support the bill in a Tuesday vote, but Brian Kennedy, a spokesman for House Minority Leader John Boehner, R-Ohio, didn't agree.